A room-temperature self-healing elastomer with ultra-high strength and toughness fabricated via optimized hierarchical hydrogen-bonding interactions

Abstract

The preparation of room-temperature self-healing polymeric materials with good healing efficiency and high mechanical strength is challenging. Two processes are essential to realise the room-temperature self-healing of materials: (a) a...

A review on room-temperature self-healing polyurethane: synthesis, self-healing mechanism and application

“…Hydrogen bond is a weak dynamic reversible noncovalent bond and its bond energy is only one tenth of that of C-C covalent bond (400 kJ/mol). Thus, the hydrogen bonds are easily broken and reformed at room temperature, so the polymers containing hydrogen bonds possess room temperature self-healing properties [37][38][39]. Generally, hydrogen bonds widely exist between the molecular chains of polyurethanes, which are mainly formed by self-assembly of proton donors (N-H) and proton receptors (C=O) in carbamate groups or urea groups.…”

“…So far, room-temperature self-healing polyurethanes mainly rely on reversible covalent bonds (such as disulfide bonds [21][22][23], diselenide bonds [24][25][26], ditelluride bonds [27,28], alkoxyamine bonds [29,30], imine bonds [31][32][33], boroxine bonds [34][35][36], etc.) and noncovalent bonds (such as hydrogen bonds [37][38][39], metal-ligand coordination bonds [40][41][42], ionic bonds [43,44], etc.) to achieve multi-ple healing cycles.…”

Preparation of ecofriendly water-borne polyurethane elastomer with mechanical robustness and self-healable ability based on multi-dynamic interactions

“…The formation of hydrogen bonds in C]O is mainly due urethane-urethane, urethaneurea, and urea-urea, in which the bonding energy of H-bond constructed by urea-urea is much higher than that with urethane-urethane. 32,45 Some of the boronic ester replaced the urea bond, where a bond with a lower bonding energy is easier to form, which may be more conducive to the formation of ordered hydrogen bonds. The presence of multiple hydrogen bonds had a positive effect on promoting the mechanical performance and self-healing capacity.…”

A healable poly(urethane-urea) elastomer with ultra-high mechanical strength enabled by tailoring multiple relaxation dynamics of hierarchical hard domains

“…10,11 For healable elastomers, the relaxation of polymer chains relies on the dynamic bonds (dynamics and concentration), 12,13 polymer chains (molecular structure, molecular weight and mobility), [14][15][16][17] and phase structure (phase separation, crystallization and llers). [18][19][20]57 To facilitate the relaxation of polymer chains, strategies such as introducing abundant dynamic bonds, 21,22 enhancing the rate of bond exchange 23,56 and improving the mobility of chain segments 24,25 have been developed. By contrast, in elastomers with high mechanical performance, reinforced molecular or microscopic structures such as strong interactions, 26,27 regular conguration 28,29 and ller nanoparticles 30,31 usually compromise healing because the uidity and relaxation of polymer chains are constrained.…”